Steel manufacture



Jan. I, 1963 R. P. A. MACKAY 3,071,363

STEEL MANUFACTURE Filed April 27, 1961 2 SheetS -Sheet 1 10 I: nii 14-22 19A 155: W 15 7 i|,i l :ilslii I I v I I. I i i.

INVENTOR RONALD PETER Ausm/R AMCKAV A TTOR/VEYS Jan. 1, 1963 R. P. A.MACKAY 3,071,363

STEEL MANUFACTURE Filed April 27, 1961 2 Sheets-Sheet 2 IN VE N TORRONALD PETER AL/STA/R MAC/(A A TTORNEYS United States PatentofilicePatented Jan. 1, 1963 3,071,363 STEEL MANUFACTURE Ronald P. A. Mackay,Abbey Works, Port Talbot, Glamorgan, Wales, assignor to The SteelCompany of Wales Limited, Glamorgan, Wales Filed Apr. 27, 1961, Ser. No.106,073 1 Claim. (Cl. 266-411) This invention relates to the applicationof oxygen in the manufacture of steel in steel refining apparatus andmore particularly the open-hearth furnace. It relates, in particular, toan improved apparatus for the injection of oxygen in the form of a jetinto the steel refining apparatus which will be hereinafter referred toas an open-hearth furnace but which is intended to cover steel refiningapparatus such as stationary and tiltable open-hearth furnaces,stationary and tiltable mixers both of the inactive and active type.

It is the main object of the invention to provide an improvement in anoxygen delivery pipe or gun which is retractibly mounted on the roof ofthe furnace for lowering through an opening in the roof. The gun is soarranged that the stream of oxygen is delivered on the charge in thefurnace in the form of a jet which is at near sonic speed and at anangle from the vertical so that the spray of molten steel and slag isdirected away from the tip of the gun which thereby greatly prolongs thelife of the gun. In this prior arrangement the angular delivery of theoxygen jet is obtained by providing the gun with a copper end bent at anangle of approximately 25 with the tip of the gun about five inchesabove the steel bath.

The present invention sets out to provide an oxygen delivery pipe or gunmodified by providing its end portion with a plurality of deliverypassages each for directing a stream of oxygen at an angle from thevertical on to the steel bath. It will be appreciated that thearrangement provides a more efiicient discharge of the oxygen stream onto the steel bath in that a greater area of the steel bath will becovered simultaneously by the discharge of a number of oxygen streams.Furthermore, for a given oxygen flow splashing is considerably reduced.The invention also sets out to provide a more efiicient cooling of sucha multi-jet gun or pipe.

According to the invention there is provided an oxygen delivery gun orpipe for use in the manufacture of steel in an open-hearth furnace, saidgun or pipe comprising an elongated barrel, a tubular member centrallylocated within said body for the passage of oxygen therethrough andterminating short of the nozzle of the gun or pipe, a plurality ofpassageways connecting the end of said tubular member with a pluralityof discharge ports spaced about the nozzle of the gun, and a pluralityof pipes angularly spaced about the tubular member for conveying coolingliquid to the nozzle of the gun or pipe, wherein two of said passagewaysare spaced apart sufliciently to allow one of said cooling pipes toextend downwardly between said passageways and into the nozzle of thegun or pipe so as to direct cooling liquid directly into the spacebetween the passageways at the end of the tubular memher.

The invention will now be described with reference to the accompanyingdrawings, in which:

FIGURE 1 is a transverse vertical cross-section of an open-hearthfurnace showing the oxygen gun of the invention in its lowered position;

FIGURE 2 is an elevational view of the oxygen gun with portions of thewall removed to show the cooling arrangements;

FIGURE 3 is a vertical sectional view of the oxygen gun in FIGURE 2;

FIGURE 4 is an enlarged sectional view taken on the line 44 of FIGURE 2and showing the arrangement of the coolant pipes about the centraloxygen tube and discharge passageways; and

FIGURE 5 is an enlarged sectional view of the tip of the gun taken onthe line 55 of FIGURE 4.

Referring now to the drawings, and more particularly to FIGURE 1 whereinlike reference numerals indicate the same parts throughout the variousviews, the oxygen gun assembly indicated at 1 is supported by a cable 2extending over a pulley 3, secured in the roof of a building containingan open-hearth furnace indicated at 4. The cable 2 extends horizontallyto another pulley 5 and down to the winding drums 6 of an electricallyoperated winch 7 secured to girders above the furnace or in any othersuitable position.

The gun assembly 1 extends downwardly through an opening Sin the roof 9of the open-hearth furnace 4. The opening 8 is in a panel of chromemagnesite bricks 10 which is inserted in the roof of the furnace 4.Located within the opening 8 is an annulus 11 which surrounds the gunassembly 1.

A guide 12 for the oxygen gun is positioned directly above the opening 8upon a 'beam construction indicated at 13. The guide is for the purposeof assisting the cable in supporting the gun in position and to preventthe gun from rotating within the furnace when it is in its operativeposition.

Proceeding next to FIGURES 2 and 3 which illustrate sembly 1 comprises acopper barrel 14 to which is affixed at the lower end thereof a castcopper nozzle 15, e.g. by welding.

Secured to the upper end of the barrel 14 is a U-shaped connectingmember 17 to which the cable 2 is attached. Extending from the upperportion of the gun body is a downwardly curved pipe 18 which is theinlet of the cooling water. The pipe'18 is connected to the open topends of three pipes 19 which extend the length of the oxygen gun andsurround a centrally located pipe 20 through which oxygen is passed.

As the cooling water emerges from the ends of the pipes 19 it passesupwardly as indicated by the arrows 22 in the space between the walls ofthe gun and the pipe 19 and 20. When the water reaches a chamber 23, itpasses outwardly through a downwardly bent pipe 24. A plate 25 separatesthe water outlet chamber 23.

As may be best seen in FIGURE 1, a hose 37 connects the water inlet pipe18 to a source of cooling water. A hose 38 connects to the water outletpipe 24 to convey the heated water to a suitable cooling source.

A hose 26 connects the oxygen pipe 20- to a source of oxygen.

Near the upper end of the gun body 14 there is a pair of radiallyextending locating bars 27. These bars are of high grade steel and areused to support and locate the gun in the gun guide 12 which not onlypositions the gun but also serves to support the gun above the furnaceshould there be a failure of the supporting cable.

Annulus 11 is used to cool the opening 8 in the roof of the open-hearthfurnace. By cooling this opening, the furnace gases escaping from theopening will be cooled and their cutting action on the roof and theposition of the hole will be considerably reduced. The annulus 11comprises a continuous length of steel tubing which is in the shape of acoil. The cooling water enters through the water inlet 34 and circulatesthrough the coil from the bottom upwardly to be exited from the wateroutlet 35. The use of a roof cooler in the form of a continuous coil hasthe outstanding advantage in that there is a constant flow of thecooling water throughout the entire annulus. This results in a constantmaximum flow rate through the entire coil. By having a constant maximumA fiow rate, the life of the water-cooled annulus is greatly improved,this improvement being on the order of a fivefold increase in the lifeof the annulus.

Referring now to FIGURES 4 and 5 it will be seen that the centrallylocated oxygen delivery pipe 20 is welded at its lower end to acorresponding pipe 39 forming part of the copper-nozzle 15. The pipe 39is closed at its lower end as indicated at 40 so as to leave a space 41between the wall 40 and the lower wall of the nozzle 15. The lower endof the wall of the pipe 39 adjacent wall 40 is formed with a pluralityof passageways 42 which extend outwardly at an angle to pipe 39 toprovide a series of discharge ports 43 in the base of nozzle 15. In thedrawings five passageways are provided. An important feature is that thepassageways 42 are not symmetrically located around the pipe 39. Asshown in FIGURE 4, the passageways 42 are located 60 apart with theexception of passageways 42A and 428 which are spaced 120 apart. Thepassageways are all inclined at an angle of about 20 to the verticalaxis of the gun so that the stream of oxygen through pipe 20 is dividedinto five separate jets each directed outwardly from the gun axis. Whenthe nozzle of the gun is located about 4 to 5 inches about the steelbath indicated at 36 there is a considerable reduction in splashingcompared with a single orifice gun. For similar oxygen delivery rates of30,000 to 60,000 cu. ft. per hour, the individual delivery rate of eachnozzle 43 is reduced to 6,000 to 12,000 cu. ft. per hour and as thestreams of oxygen are directed outwardly from the gun there is aconsiderable increase in the life of the gun and less damage to thefurnace walls due to the reduction in splashing.

An important problem of the gun of the present invention'is thenecessity of providing adequate cooling of the nozzle 15 around thepassageways 42 otherwise the life of the gun is short. The passageways42 tend to restrict the flow of cooling water from the pipes 19 whichwith a symmetrical arrangement of the passageways 42 would largelyresult in the cooling water emerging from the ends of the pipes 19 andreturning directly up the space between the pipes 19 and 20 and the gunbarrel 14. As shown two of the pipes 19 extend downwardly to thebeginning of passageways 42 but by providing the space 44 betweenpassageways 42A and 42B it is possible to extend the other cooling waterpipe 19A downwardly to a position adjacent the lower wall of nozzle 15.The end 45 of pipe 19A is angled so as to ensure that the discharge ofthe cooling water is directed into the space 41 between the passageways42 as indicated by the arrows 46. In this manner an efficient cooling ofthe nozzle is obtained which is essential if an economic life for thegun is to be obtained.

If desired, more than one gun may be provided. By the delivery of oxygenin accordance with the invention through the root of the furnace andproviding means for retracting the gun or guns, other operationsessential to the open-hearth furnace, such as charging, and tapping thefurnace, are not interfered with in any way and the invention may thusbe easily applied to existing furnaces. The manipulation of the deliverypipe assembly is extremely simple and the operation requires very littlemanual attention.

I claim:

An oxygen delivery gun for use in open-hearth furnaces comprising anelongated barrel having a closed lower end with five nozzle outlets, atube positioned centrally in said barrel and having five downwardlyextending and radially diverging nozzles, each of which terminates inone of the nozzle outlets, four of the five passageways between nozzlesbeing angularly displaced from one another and the remaining widepassageway being angularly displaced from each of the two adjacentpassageways, three equally spaced pipes extending downwardly in thespace between the barrel and the tube, one of the pipes extending alongthe middle of the wide passageway and terminating close to the lower endof the barrel while the other two pipes terminate at a higher level,means for delivering cooling water into the upper ends of the pipes, andmeans for delivering oxygen into the upper end of the barrel.

References Cited in the file of this patent UNITED STATES PATENTS1,849,072 Clark Mar. 15, 1932 2,807,506 Gehring Sept. 24, 1957 2,827,279Cox Mar. 18, 1958 2,836,411 Auer May 17, 1958 2,937,864 Kesterton May24, 1960 FOREIGN PATENTS 852,078 Great Britain Oct. 26, 1960

